1. Field of the Invention
The present invention relates to a locking mechanism for a tray used in an automotive seat, on which a cup, a bottle of or canned beverage, or other small articles is placed, and is particularly directed to a locking mechanism for locking and unlocking an armrest tray of the type accessible from the recessed area in the seat back of the seat, wherein the tray is rotatatively drawn out or returned into the recessed area so as to be placed upon the armrest for use or stored in a non-use sate in the seat, or such an armrest tray of the type used in a trunk-through rear seat, in which the tray is rotatably provided in in the trunk-through opening of the seat leading to the interior of the trunk room of the automobile and when in use on the armrest, the tray acts as a protector plate for protecting the upper surface of the arm rest against such a long article as a ski sled or the like, or if not so, the tray is used as it is for some cups or canned beverage to be placed thereon, and when in no use, the tray is strored in the trunk-through opening, serving as a wall that partitions the seat side and trunk room.
2. Description of Prior Art
As stated in the field of the invention above, there has been known an armrest tray of the type accessible from the recessed part of seat or of the type used in a trunk-through rear seat. In both two types of trays, the tray is rotatably drawn out for use on the armrest or returned into the seat for non-use stored position. The tary is locked or unlocked by means of a locking mechanism in order to cause it into the non-use state or release it from the locked state for the use state.
To assure the locking and unlocking of the tray, the action of the locking mechanism therefor reqruires a rapidity and ease in terms of its operationability and thus it has been desired that the locking/unlocking action should be effected simultaneously with the drawing-out/returning of the tray.
Meeting such demand, a magnetic force has been received attention to effect locking or unlocking of the tray, and there has been made available a magnetic automotive-tray locking mechanism, according to which, for instance, a magnet is provided at the tray-storage area of the seat while a metallic piece is provided at the tray, so as to effect a positive locking of the tray when returning it to the non-use storage area of the seat. At the locking, the tray is magnetically attracted and secured to the seat by the reason that the metallic piece of the tray is forcibly attached to the magnet of the tray-storage area of the seat. Reversely, when its unlocking is desired, the tray is drawn out from that storage area, overcoming the magnetic force exerted between the magnet and metallic piece, so that the tray is rotated down to rest on the armrest for use.
However, a drawback has been found with such conventional magnetic tray locking mechanism, in that the locked state of the tray is easily released under an "inertia" force which is produced in the repeated increase and decrease of the driving speed of the vehicle, such as an automobile, train, bus or airplane, thus raising the possibility of the stored tray being unexpectedly thrown out into a usestat, presenting an undesired trouble on the part of an occupant on the seat.
Even if a magnet of increase magnetic force is utilized in the locking mechanism to prevent such unexpected unlocking of the tray, there will be such an inconvenience that a much more force is required by the occupant who intends using the tray to overcome the increased magnetic force, thus deteriorating the unlocking operation.